If you're running a PC with Symantec's pcAnywhere, beware. New risks have been raised that could affect hundreds of thousands of users.

Last month, Symantec recommended that its pcAnywhere customers disable or uninstall the while the company worked on fixes. Several patches were released, most recently an all-in-one patch Feb. 10. Following that release, Symantec indicated the software was safe to use, in conjunction with standard security best practices.

The software is typically used by workers and others to access an office computer from the road.

Source Code Theft

But Boston-based security firm Rapid7 has recently estimated that as many as 200,000 PCs are running unpatched versions -- meaning versions that are exposed, although not necessarily vulnerable. These include up to 5,000 point-of-sale systems that could be connected to financial systems in businesses, which could include credit card information.

In addition, Alert Logic, a security company based in Texas, has posted test code that could crash patched or unpatched PCs running pcAnywhere, via a denial-of-service attack that some observers believe could be used to hijack the .

Symantec's unusual move to recommend the disabling or uninstalling of its own software was in response to the 2006 theft of its source code, which the company only revealed in January. The company told the Reuters news service last month that the source code to its flagship Norton security software had been stolen in 2006, and that an internal investigation has shown the breach came from its own servers.

Previously, Symantec had said that the code had been stolen from a third party. There had been some evidence that it might have come from an Indian government server.

The internal investigation followed an extortion against Symantec by an individual claiming to be part of Anonymous, who sought a payment in exchange for not posting the source code. Symantec said it did not comply and the code was released.

'Slightly Increased Security Risk'?

In a report published at the time, the company said "the encoding and encryption elements within pcAnywhere are vulnerable" on an unpatched machine. It added that "successful man-in-middle attacks may occur depending on the configuration and use of the product," and that a malicious user could steal session data or credentials.

The company also said that, if the cryptographic key was stolen, a hacker could launch remote control sessions that gave control not only of the machine, but possibly of other machines on a network.

But Symantec also said that "the code that has been exposed is so old that current out-of-the-box security settings will suffice against any possible threats that might materialize as a result of this incident," although the company then released patches. At the time of the source code announcement, Symantec had said that pcAnywhere customers could be looking at "a slightly increased security risk."

But an unsigned posting last week to the Web site of security training company InfoSec Institute, claiming to be from a security researcher, said the source code for the current pcAnywhere is essentially the same code that had been posted, with only minor changes to keep the software compatible with newer versions of Microsoft Windows.